The present invention relates to medical equipment and, more particularly, to methods and apparatus for staining specimens deposited on slides.
Currently, many medical tests are performed by examining a biological specimen, e.g., blood, pus, or urine, applied to a slide, such as a conventional glass microscope slide. Typically, the biological specimen is xe2x80x9csmearedxe2x80x9d onto the slide and, then, treated with a reagent, such as a stain, to make features of the smeared biological specimen more visible. Often, the slide is then rinsed to remove excess reagent and dried for handling by laboratory personnel.
Automated slide stainers are available which automate the process of staining, rinsing, and drying smeared slides. One type of automated slide stainer is a dip and dunk slide stainer. In a dip and dunk slide stainer, one or more reagents are applied to slides by dipping the slides into one or more vessels containing these reagent. The slides are then rinsed by dipping the slides into a rinsing vessel, supplying water (or rinse solution) to the rinsing vessel, such that the water passes over the slides, and removing the slides from the rinsing vessel. Finally, the slides are dried by circulating air over them.
During the rinsing process, water supplied by a water supply line enters the rinsing vessel through an opening in the bottom of the rinsing vessel, thereby introducing water and causing the water within the rinsing vessel to circulate over the slides. Excess water, along with any reagents removed from the slide, exits the rinsing vessel through an opening near the top of the rinsing vessel. If the flow rate of the water into the rinsing vessel is too low, the slides will not be cleaned adequately, e.g., excess reagent will remain on the slides. On the other hand, if the flow rate is too high, the smeared biological specimen may be damaged or destroyed.
Typically, the flow of water is set using a manually operated valve. The valve is positioned in a rinse line between the water supply line and the opening in the bottom of the rinsing vessel. The valve is manually adjusted through trial and error to achieve an appropriate flow of water into the rinsing vessel. Thus, the appropriate flow is not precise and significant set-up time is required to achieve the appropriate flow. In addition, if the water pressure in the water supply line changes, e.g., due to a flushed toilet, an opened faucet, or other water supply line fluctuations, the flow of water changes, thereby increasing the potential for inadequately rinsed slides and/or damaged specimens.
Accordingly, there is a need for a slide stainer with controlled fluid flow for controlling the flow of rinse fluid supplied by a supply line to adequately rinse slides without damaging or destroying smeared biological specimens. The present invention fulfills this need among others.
The present invention is a slide stainer with controlled fluid flow. The slide stainer overcomes the aforementioned problems by controlling the flow rate of fluid, e.g., rinse fluid, from a fluid supply line that is applied to the slides. By controlling the flow rate of the fluid applied to the slides, a proper flow rate can be maintained regardless of the fluctuations in the flow in the supply line, thereby guarding against inadequately rinsed slides and/or damaged specimens.
In accordance with one aspect of the invention, fluid from a fluid supply line passes through a controlled flow device that can be controlled to regulate the flow rate of the fluid. The flow rate is sensed by a sensor, which produces a flow rate signal indicative of the sensed flow rate. Based on the flow rate signal, a controller generates a flow control signal for controlling the controlled flow device to control the flow rate of the fluid.